Validation study of the Prague Barrett’s C&M Criteria

Validation study of the Prague Barrett’s C&M Criteria

Prateek Sharma, M.D.Kansas City, USA

Chairman of the Barrett’s Oesophagus Working Subgroup of the International Working Group for the Classification of Oesophagitis

• The aim of this exercise was to develop and validate explicit, consensus-driven criteria for the endoscopic diagnosis and grading of Barrett’s Esophagus

• An international working group agreed on criteria and developed materials which included video endoscopic recordings gathered in a standardized manner

• The criteria included assessment of the Circumferential (C) and Maximum (M) extent of the endoscopically visualized Barrett’s segment and other endoscopic landmarks

The Development and Validation of an Endoscopic Grading System for Barrett’s

Esophagus: The Prague Barrett’s C&M Criteria

Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

Aims of the validation study of the Prague Barrett’s C&M Criteria

To determine inter-observer agreement on: • Circumferential extent of Barrett’s • Maximum extent of Barrett’s • Location, by cm of endoscope insertion of:

– gastro-esophageal junction– diaphragmatic hiatus

Validation study materials (1)

• Best possible image quality video-endoscopic recordings were made during 1 cm stepwise withdrawals of the endoscope from the upper stomach to above the maximum extent of endoscopic columnar metaplasia

• Every attempt was made to display landmarks and other pertinent findings at each cm withdrawal station

• The depth of endoscope insertion in cm from the incisors was documented during withdrawals and edited onto the video clips beside the endoscopic image

Validation study materials (2)

• The video clip collection was reviewed by the Working Subgroup and the 29 most suitable clips were selected for scoring in the validation study

• The selected video clips showed a full spectrum of different lengths and findings in relation to esophageal columnar metaplasia

• The Working Subgroup developed detailed instructions and a standard score sheet for each video clip

Validation study processes

• The numerically coded selected video clips arranged in random order, the instructions for evaluation, and the score sheets were sent on a DVD to 29 assessors in 14 countries

• The selected assessors all had a strong interest in Barrett’s Esophagus

• Assessors returned score sheets on each video clip to a central data collection point for entry into a database and analysis

Contributing assessors

• R. Ackroyd U.K• A. Barkun Canada• T. Clarke Australia• G. Costamagna Italy• A. Edebo Sweden• R. Enns Canada• G. Falk USA• P. Fockens

Netherlands• J. Hatlebakk Norway• R. Holloway Australia• G. Holtmann Australia• P. Katelaris Australia• A. Kruse Denmark• N. Marcon Canada• G. May Canada

• S. Nandurkar Australia• H. Neuhaus Germany• M-A. Ortner Switzerland• G. Overholt USA• U. Peitz Germany• J. Regula Poland• J-F. Rey France• R. Sampliner USA• M. Schoeman Australia• S. Spechler USA• N.B. Vakil USA• J.L. Van Laetherm Belgium• K. Wang USA• H. Worth Boyce USA

Criteria for assessing the validation study video clips

• For all landmarks, depth of insertion of endoscope was recorded, at the point where the feature was located

• Assessors were instructed to locate the gastro-esophageal junction by either the most proximal position of the gastric folds or by the circumferential ring or pinch

• Similarly, the assessors also recorded the position of the diaphragmatic hiatus and the circumferential and maximum extents of esophageal columnar metaplasia

Validation study data analysis

Inter-observer agreement was evaluated with the:• Reliability coefficient: a measure of agreement when

there are more than 2 observers which compensates for agreement by chance

Reliability coefficient

<0.4 Poor

0.4-0.75 Fair/Good

>0.75 Excellent

Results - the Prague Barrett’s C&M Criteria validation study

• 22 assessors completed all ‘C’ and ‘M’ values for all 29 video clips

• These data were used for analysis

• Reliability coefficient values for both ‘C’ and ‘M’ were in the excellent range

Prague Barrett’s C&M Criteria: Results

Reliability coefficient values for

• ‘C’ extent 0.94 (95% CI: 0.91-0.97)

• ‘M’ extent 0.93 (95% CI: 0.89-0.96)

Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

Prague Barrett’s C&M Criteria: Results

Reliability coefficient values for

• Proximal margin of gastric folds 0.88

• Pinch at the distal esophagus 0.78

• Diaphragmatic hiatus 0.85

Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

Prague Barrett’s C&M Criteria: Results

Kappa values for

• Barrett’s any length 0.49

• Barrett’s length < 1cm 0.21

• Barrett’s length > 1cm 0.72

Sharma P, Dent J, Armstrong D et al., Gastroenterology 2006

Summary - Validation of the Prague Barrett’s C&M Criteria

• The Prague Barrett’s C&M Criteria represent a major advance in the endoscopic recognition and grading of Barrett’s Esophagus

• The reliability of these criteria is excellent

• Endoscopic recognition of lengths of Barrett’s <1 cm has very low reliability